|Above: WU depiction of NWS/NEXRAD radar at 1:09 am EDT Wednesday, September 5, 2018, just after Tropical Storm Gordon came ashore on the Mississippi coast.|
Fast-brewing Tropical Storm Gordon ended its sprint across the Gulf at around 11:15 pm EDT Tuesday night, making landfall just west of the Mississippi/Alabama border with top sustained winds estimated at 70 mph. Gordon’s impact on the coast was muted by its irregular structure. The storm never developed a solid, complete eyewall, despite several attempts to do so. By 1 am EDT Wednesday, Gordon's top winds had dropped to 50 mph. The storm was centered about 40 miles west of Mobile, AL, continuing northwest at a steady 14 mph.
Top sustained winds near Gordon on Tuesday night included 56 mph at Dauphin Island, AL, and 68 mph (gusting to 78 mph) at Fort Morgan, AL. Both sites are located at the south end of Mobile Bay, so they were affected by Gordon’s northern and eastern eyewall. The Dauphin Island reading was collected from a height of 44 feet and the Fort Morgan reading from 119 feet. It’s possible that no comparably strong winds will be reported from anemometers at a standard height of 10 meters (33 feet). See our two-part report from April on the challenges of measuring and assessing hurricane winds at landfall.
Even tropical-storm-force winds (sustained at 39 mph or greater) can be quite dangerous, as they can easily bring down trees and power lines, especially when the soil has been saturated by heavy rain. Escambia County authorities said that at least one person was killed Tuesday evening when a tree fell onto a trailer in West Pensacola, FL. At least 21,000 power outages were reported across coastal Alabama late Tuesday, and water overtopped highways in some flood-prone areas, including western Dauphin Island.
See the frequently updated weather.com article for more on Gordon’s impacts.
|Figure 1. Charles Phanthapannha stands in the rain outside a bar as Tropical Storm Gordon approaches on Tuesday, Sept. 4, 2018 in Mobile, Ala. Image credit: AP Photo/Dan Anderson.|
Gordon’s rains will spread far and wide
Some 3” to 6” of rain fell across coastal Alabama and the far western Florida panhandle as Gordon approached, and localized totals could end up topping 12” before the storm departs. This is just the beginning of Gordon’s watery siege, though. Widespread 4” – 8” rains, with a few higher totals, are expected along a swath roughly 50 – 100 miles wide as Gordon heads northwest.
By Wednesday night into Thursday, Gordon’s circulation will slow to a crawl across southern Arkansas as its rain continues. Gordon will most likely be a tropical depression or post-tropical low by that point. However, it will be embedded in a very moist atmosphere and very low wind shear, so I wouldn’t be shocked to see Gordon briefly looking more symmetric across the lowlands of Arkansas on Thursday than at landfall on Tuesday night (though its top sustained winds will be considerably weaker by then). Think Tropical Storm Alberto, which pulled off a similar trick in spectacular fashion across Indiana in late May.
As Gordon’s remnants weaken across the Ozarks, the storm’s moisture will be shunted north and east into a zone of converging air expected to develop from Missouri to Pennsylvania. Rains from Thursday into the weekend could total 2” to 8” along this broad band, which could end up further north or south as the situation evolves. Parts of the Midwest hard hit by very heavy rains over the past few weeks will need to keep a close eye on Gordon's remnants.
Flooding may also become a concern across Texas, where some of Gordon’s moisture will be channeled. Heavy rains hammered the San Antonio area on Monday, prompting more than 60 water-rescue calls. A CoCoRaHS volunteer in northeast Bexar county reported 10.18”, and the National Weather Service total of 6.07” made Monday the third wettest September day in 133 years of recordkeeping for San Antonio.